<!DOCTYPE html>
<html lang="en">
<head>
   <meta charset="UTF-8">
   <meta name="viewport" content="width=device-width, initial-scale=1.0">
   <title>title</title>
</head>
<body>
   <!-- localStorage本地级别存储，大小不能超过5M
        api是
        localStorage.setItem('k','v')
        localStorage.getItem('k') //没有值返回null
        localStorage.removeItem('k')
        localStorage.clear()
        JSON.parse(null)的值是null
    -->
   
</body>
</html>